#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
char* my_strstr(const char* str1,const char* str2)
{
	const char* s1 = str1;
	const char* s2 = str2;
	const char* p = str1;
	while (*p != '\0')
	{
		s1 = p;
		s2 = str2;
		while (*s1 != '\0' && *s1 != '\0' && *s1 == *s2)
		{
			s1++;
			s2++;
		}
		if (*s2 == '\0')
		{
			return (char*)p;
		}
		p++;
	}
	return NULL;
}
int main()
{
	char arr1[] = "Hello World";
	char arr2[] = "World";
	char* ret = my_strstr(arr1, arr2);
	if (ret != NULL)
		printf("%s", ret);
	return 0;
}